This invention relates to a method of manufacturing a conductor pattern for use as a wiring in a semiconductor device.
In accordance with this invention, the method is applicable to whichever of semiconductor devices known at present. The conductor pattern is manufactured on an insulator surface of an insulator layer formed on a semiconductor substrate of the semiconductor device. The insulator layer is for electrically insulating the conductor pattern selectively from other parts of the semiconductor device.
In the manner which will later be described in greater detail, a conventional method of manufacturing a conductor pattern on an insulator surface formed on a semiconductor substrate comprises the steps of: (A) forming a first conductor film on the insulator surface with either aluminium or tungsten to a thin film thickness; (B) patterning the first conductor film in compliance with the conductor pattern into a patterned film having a patterned surface; and (C) selectively growing a second conductor film with aluminium on the patterned surface to provide the conductor pattern of a desired thickness. When manufactured in accordance with the conventional method as a conventional pattern, the conductor pattern has various drawbacks as follows.
Selective growth of the second conductor film is for increasing the thin film thickness to the desired thickness. During the selective growth, the second film inevitably laterally grows. This gives a reversedly or inversedly tapered side surface to the conventional pattern.
As a consequence, the conventional pattern is unavoidably provided with a part which has a wide pattern width and is liable to undesiredly short circuited either with a different part of the conventional pattern, namely, in the conductor pattern, or with a like pattern manufactured on the insulator surface. Such a conductor pattern is often covered with a covering film of an insulating material. The reversedly tapered side surface adversely affects coverage of the conventional pattern with the covering film.
The selective growth must therefore be restricted. This restriction gives a thin total thickness to the conventional pattern. In other words, it has been very difficult to actually give the desired thickness to the conventional pattern. This difficulty has often resulted in an objectionable break in the conventional pattern particularly when a fine pattern of a narrow pattern width must be given to the conventional pattern.
Manufacture of a like two-film conductor pattern is described in a paper which was published under the title of "Applications of Selective Tungsten on Aluminium in Multilevel Metal Technologies" and was read by J. L. Yeh and five others in V-MIC Conference held by the IEEE on Jun. 15-16, 1987. Creation of a dielectric side wall is mentioned in the Yeh et al paper.